This invention is concerned with a mould arrangement for use in a cyclicly operating glassware forming machine, the arrangement comprising two supports on each of which one of two opposed side portions of a mould is mounted, each side portion defining side portions of a cavity of the mould which has an upwardly-facing opening through which molten glass can be introduced into the cavity to be moulded to the shape of the cavity, the supports being movable in a cycle of operation of the machine to a first position thereof, in which the side portions engage one another to co-operate in defining the mould cavity so that moulding can take place, and to a second position thereof, in which the side portions are separated from one another so that the moulded glass can be removed from the mould.
In a glass container manufacturing machine of the so-called "individual section" type, a number of container making units or sections are arranged side by side, are fed with glass from a common source, and feed their output to a common conveyor. Each of these sections has a parison mould arrangement by which a parison is formed from a gob of molten glass delivered thereto, and a blow mould arrangement by which parisons are blown to the shape of the container. Both the parison mould arrangement and the blow mould arrangement comprise two supports and mould side portions as described in the last preceding paragraph. The side portions of the parison mould arrangement co-operate with neckrings of an invert mechanism of the machine to form a parison mould, the invert mechanism being operable to transfer parisons from the parison mould arrangement to the blow mould arrangement. The side portions of the blow mould arrangement co-operate with a stationary bottom plate to form the blow mould. The parison is formed in the parison mould arrangement in an inverted condition either by pressing or by blowing and is inverted as it is transferred to the blow mould arrangement where it is blown to the shape of the required article of glassware.
Since the moulds of an individual section type machine absorb heat from the glass at the rate which is faster than the heat can be dissipated to the surrounding atmosphere without additional cooling, such moulds are supplied with cooling means which cool the mould so that it remains at a substantially constant average temperature during successive operations of the machine. Because the sections of an individual section type machine need to be close together, for reasons of glass supply, only very limited space is available around the mould for the provision of cooling means. One solution to this problem is to feed cooling air through the frame of the machine section to a vertical cooling stack which is provided with nozzles which direct the air on to the outside of the mould. This solution, however, has the disadvantage that the supports supporting the side portions of the mould interfere with the flow of air to the mould and also it is difficult to provide differential cooling around the mould as is desirable. Furthermore, such cooling stacks are a source of undesirable noise. In another type of cooling means, cooling air is supplied through the supports to a chamber around the mould. This type has the disadvantage that it requires expensive machining of the supports, to allow both for the movement of the supports and for the flow of the cooling air. Furthermore, as a seal has to be provided between the support and the side portion of the mould, delays occur in changing moulds and the cost of the mould is increased. It is also difficult to provide differential cooling around the mould. Attempts have also been made to cool moulds by passing cooling air through passages in the side portions thereof. Examples can be found in U.K. Patent Specification No. 1337292 and U.S. Patent Specification No. 4251253 (FIGS. 10 to 12). In these arrangements, air is brought through the supports to the passages through pipes. Thus, expensive machining of the supports is required and also pipe connections are involved between the supports and the mould portions thereby causing delay to mould changes and increasing the cost of the moulds. Furthermore, in these arrangements the cooling air makes sharp changes of direction in the mould so that considerable resistance to the air flow is created requiring the use of high pressure air to achieve adequate air flow. The use of high pressure air is undesirable because of the expense involved. Furthermore, non-uniform air flow is created distorting the cooling effect and making it difficult to predict. Thus, it becomes difficult to predict where to position the cooling passages to achieve the optimum cooling effect. If the passages are not initially correctly positioned, the cooling effect can be adjusted by inserting plugs or insulating sleeves into the passages but this is a time-consuming trial-and-error method because the effects of the plugs and/or sleeves are again hard to predict.
In the specification of European Patent Application No. 83304985.1, (Publication No. 01 02 820) there is described a mould arrangement in which passages in the side portions of the mould can be supplied with cooling air at a substantially uniform pressure and with a uniform flow pattern so that the above-mentioned disadvantages of previous cooling systems are overcome. In that mould arrangement, the cooling passages in each side portion each have an entrance in a bottom surface of that side portion and the mould arrangement also comprises a plenum chamber extending beneath the first or the second position of each side portion and having one or more exits which open upwardly and communicate, when the side portion is above the plenum chamber, either directly or through vertical passages in a bottom plate of the mould with the entrances of the cooling passages so that air is supplied to each cooling passage at substantially the same pressure, the plenum chamber also having an entrance connected to air supply means operable to blow air into the plenum chamber. This mould arrangement achieves excellent results with blow mould arrangements but is difficult to apply to parison mould arrangements because of the presence beneath the side portions of the mould of the neckring and either a parison blowing arrangement or a parison pressing arrangement.
It is an object of the present invention to provide a mould arrangement in which passages in the side portions of the mould can be supplied with cooling air at a substantially uniform pressure and with a uniform flow pattern and which is readily applicable to parison mould arrangements.